1. Nadia Fomin University of Virginia
Inclusive Scattering from Nuclei at x>1 and High Q2 with a 5.75 GeV Beam
Nadia Fomin
University of Virginia

2. Physics topics we can study at x>1
Momentum distributions of nucleons inside nuclei
Short range correlations (the NN force)
3-Nucleon correlations
Comparison of heavy nuclei to LD2 and 3He
Scaling (x, y) at large Q2
Constraints on the high momentum tail of the nuclear wave function
Structure Function Q2 dependence

3. Quasielastic scattering: an example (Deuterium)

4. Electron scattering and x ranges
Scattering from a free nucleon: 0<x<1 :
x=1 (elastic)
x<1 (inelastic)
x > 1:
momentum is shared between nucleons, so 0<x<A
 probing the effect of nuclear medium on quark distributions
 kinematics determine whether the electron scatters from quarks or hadrons
Regions being probed:
 Low Q2 – entire nucleus (elastic)
 Intermediate Q2 – single nucleon (Quasielastic Scattering – QES)
 Higher Q2 – DIS (“superfast” quarks at x>1)
x>1 probes the QES and DIS regions

5. Y-scaling Introduced by Kawazoe and West in 1975
Scaling function F(y) can be extracted from the measured cross-section if QES is the dominant reaction mechanism
F(y) is defined as ratio of the measured cross-section to the off-shell electron-nucleon cross- section times a kinematic factor
At large q, neglecting momenta perpendicular to q and using energy conservation
In general, F=F(y,Q2), but the Q2 dependence vanishes at high momentum transfer
n(k) is the nucleon momentum distribution
Scaling breaks down if there are significant Final State Interactions between the struck nucleon and the residual nucleus, but this should also vanish at sufficiently high Q2

6. Y-Scaling (Example: 3He)
y is the momentum of the struck nucleon parallel to the momentum transfer.
0.1<Q2<3.9

7. E Details
E is currently running at Jefferson Lab in Hall C
E is an extension of E89-008, but with higher E (5.75 GeV), Q2 , x and y.
Cryogenic Targets: LH2, LD2, 3He, 4He
Solid Targets: C, Cu, Au.
Spectrometers: HMS and SOS

8. Experimental Setup in Hall C
HMS
SOS

9. High Momentum Spectrometer
Superconducting magnets in a QQQD configuration
Maximum central momentum of 6.0 GeV/c with 0.1% resolution and a momentum bite of ±10%
Solid angle of 6.7 msr
Detectors
2 sets of Drift chambers
2 sets of x-y hodoscopes
Gas Čerenkov detector
Lead glass shower counter
Pion Rejection of ~75,000 using the Čerenkov and the Lead Glass Shower Counter

10. Short Orbit Spectrometer
For E02-019, the SOS is primarily used to estimate the charge symmetric background.
Has a solid angle of 7 msr and a large momentum bite (±20%)
Maximum central momentum of 1.75 GeV/c
QDD magnet configuration (non-superconducting):
Pion Rejection of ~10,000 using the Čerenkov and the Lead Glass Shower Counter
Detector Package is very similar to that of HMS

11. New Frontiers
Existing data

12. 3He online spectrum

13. Summary To date, we’ve taken over 60% of the data
This experiment will provide data over an extended kinematic range and significantly improve the 3He and 4He data sets
Preliminary results should be ready by next year’s DNP meeting (see you in Hawaii)

14. E Collaboration
Argonne National Lab
California Institute of Technology
Hampton University
Thomas Jefferson National Accelerator Facility
University of Basel (Roman Trojer)
University of Virginia

15. New Frontiers
Existing data